Electromagnetic wave shield material and process for producing the same

ABSTRACT

The present invention is to provide an electromagnetic wave shielding material which comprises a transparent substrate and a fine line pattern formed thereon, wherein the fine line pattern comprises a metal plating film using a physically developed metal silver as a catalytic nucleus and
         a process for preparing an electromagnetic wave shielding material which comprises exposing a light-sensitive material having a physical development nuclei layer and a silver halide emulsion layer on a transparent substrate in this order, precipitating metal silver with an optional fine line pattern onto the physical development nuclei layer by physical development, then, removing a layer provided on the physical development nuclei layer, and subjecting to plating a metal with the use of the physically developed metal silver as a catalytic nucleus.

TECHNICAL FIELD

The present invention relates to an electromagnetic wave shieldingmaterial which is equipped with a device to which various electronicequipments, communication devices such as a display device, etc., andhaving both of good light transmittance and a good shielding property ofelectromagnetic wave, and a process for preparing the same.

BACKGROUND ART

In recent years, accompanying with rapid progress of social information,technologies regarding information-related appliances are also rapidlyprogressing and spreading. Various electronic equipments, communicationdevices and display device such as CRT, liquid crystal, EL, PDP and FEDhave been used for televisions, personal computers, displays for showinginformation at a station or an airport, and for providing other variouskinds of information.

It has been worried about an effect of electromagnetic wave irradiatedfrom these electronic equipments or communication devices. For example,the problem that this electromagnetic wave causes malfunction ofneighboring machines or bad influence to human body are considered, sothat demands for an electromagnetic wave shielding material becomeshigher and higher. To comply with such demands, various transparentconductive films (electromagnetic wave shielding material) have beendeveloped. For example, they are disclosed in Japanese Unexamined PatentPublications No. Hei. 9-53030, No. Hei. 11-126024, No. 2000-294980, No.2000-357414, No. 2000-329934, No. 2001-38843, No. 2001-47549, No.2001-51610, No. 2001-57110, No. 2001-60416, and the like.

As a process for preparing these electromagnetic wave shieldingmaterials, it has generally been employed a method in which a conductivemetal such as silver, copper, nickel, indium, etc., or a conductivemetal compound of these metals is formed on a transparent resin filmsubstrate as a metal thin film by a sputtering method, an ion platingmethod, an ion beam assist method, a vacuum deposition method, or a wetcoating method. However, when a film thickness or pattern fine linewidth is set with a degree that the transparency can be maintained, asurface resistance of the conductive layer becomes so large to cause asto cause small shielding effect, so that there is a problem that, forexample, it is difficult to obtain a shielding effect of 30 dB or higherover higher frequency bands of 300 MHz or higher. Accordingly, anelectromagnetic wave shielding material having high transparency andexcellent in shielding property over higher frequency band region hasbeen desired. Also, in recent years, demands of the electromagnetic waveshielding material are expanded, and a preparation process that is lowcost and has high productivity has been desired.

In Japanese Patent Publication No. Sho. 42-23745, a technique forforming a conductive layer comprising physically developed silveraccording to a silver complex diffusion transfer development method (DTRdevelopment method) by applying a silver halide emulsion layer and asilver halide solvent (silver complex salt-forming materials). However,as mentioned above, to comply with a light transmittance with a totalluminous transmittance of 50% or more and a conductivity with a surfaceresistance of 10 ohm/□ (10 Ω/square) or less are simultaneouslysatisfied, which are required for an electromagnetic wave shieldingmaterial in recent years, it could not be accomplished by thetechnologies disclosed in the above-mentioned patent publications.

Accordingly, an object of the present invention is to provide anelectromagnetic wave shielding material having high conductivity and ahigh total luminous transmittance even when a fine line pattern with afine line width which causes a higher aperture rate is provided. Anotherobject of the present invention is to provide a process for preparing anelectromagnetic wave shielding material having high conductivity and ahigh total luminous transmittance with low cost and high productivity.

The above-mentioned objects of the present invention have been basicallyaccomplished by an electromagnetic wave shielding material in which ametal is plated by using physically developed metal silver as acatalytic nucleus.

A basic process for preparing an electromagnetic wave shielding materialof the present invention comprises dissolving silver halide with asoluble silver complex salt-forming agent to make a soluble silvercomplex salt, and simultaneously reducing it with a reducing agent(developing agent) such as hydroquinone, etc., to precipitate physicalmetal silver with an optional fine line pattern on a physicaldevelopment nuclei, and subjecting to plating with a metal such ascopper, nickel, etc., using the physically developed silver as acatalytic nucleus, which applies a DTR development method known as thephotographic development method.

SUMMARY OF THE INVENTION

The electromagnetic wave shielding material of the present inventioncomprises a transparent substrate and a fine line pattern formedthereon, wherein the fine line pattern comprises a metal plating filmusing a physically developed metal silver as a catalytic nucleus.

Also, a process for preparing the electromagnetic wave shieldingmaterial of the present invention comprises exposing a light-sensitivematerial having a physical development nuclei layer and a silver halideemulsion layer on a transparent substrate in this order, precipitatingmetal silver with an optional fine line pattern onto the physicaldevelopment nuclei layer by physical development, then, removing a layerprovided on the physical development nuclei layer, and subjecting toplating a metal with the use of the physically developed metal silver asa catalytic nucleus.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, the present invention is explained in detail.

As the transparent substrate to be used in the present invention, aplastic resin film which is transparent at visible region, havingflexibility, and preferably having good heat resistance may bementioned. As a transparency, it may be a transparency with a totalluminous transmittance of 70 to 90% or so, but in view of maintainingthe total luminous transmittance as an electromagnetic wave shieldingmaterial to a higher value, higher total luminous transmittance of thetransparent substrate is more preferred. Such a transparent substratemay include, for example, a polyester resin such as polyethyleneterephthalate, etc., diacetate resin, triacetate resin, acrylic resin,polycarbonate resin, polyvinyl chloride, polyimide resin, polyamideresin, etc., which is a single layer or a complex film with a thicknessof 10 to 600 μm.

Onto the transparent substrate, a physical development nuclei layer hasbeen provided previously. As the physical development nuclei, fineparticles (a particle size thereof is 1 to several tens nm or so)comprising a heavy metal or a sulfide thereof may be used. For example,there may be mentioned a colloid of gold, silver, etc., or a metalsulfide in which a water-soluble salt of palladium, zinc, etc., and asulfide are mixed. A fine particle layer of these physical developmentnuclei can be formed on the transparent substrate by the vacuumdeposition method, cathode sputtering method, coating method, etc. Inview of production efficiency, the coating method is preferablyemployed. A content of the physical development nuclei in the physicaldevelopment nuclei layer is suitably 0.1 to 10 mg or so per 1 m² with asolid content.

An adhesive layer comprising a polymer latex layer such as vinylidenechloride, polyurethane, etc. may be provided onto the transparentsubstrate, and an intermediate layer comprising a hydrophilic bindersuch as gelatin, etc. may be formed between the adhesive layer and thephysical development nuclei layer.

The physical development nuclei layer may preferably contain ahydrophilic binder. An amount of the hydrophilic binder is preferably 10to 300% by weight or so based on the amount of the physical developmentnuclei. As the hydrophilic binder, gelatin, Gum Arabic, cellulose,albumin, casein, sodium alginate, various kinds of starches, polyvinylalcohol, polyvinyl pyrrolidone, polyacrylamide, a copolymer ofacrylamide and vinyl imidazole, etc., may be used. The physicaldevelopment nuclei layer may contain a crosslinking agent of thehydrophilic binder.

For coating the physical development nuclei layer or an intermediatelayer, etc., it can be carried out by, for example, a coating systemsuch as a dip coating, a slide coating, a curtain coating, a barcoating, an air knife coating, a roll coating, a gravure coating, aspray coating and the like. In the present invention, the physicaldevelopment nuclei layer is preferably provided by the above-mentionedcoating method generally as a continuous and uniform layer.

In the present invention, as a supplying method of the silver halide forprecipitating metal silver onto the physical development nuclei layer,there are methods including a method in which a physical developmentnuclei layer and a silver halide emulsion layer are integrally providedin this order onto a transparent substrate, or a method in which asoluble silver complex salt is supplied from a silver halide emulsionlayer provided on another substrate such as paper or a plastic resinfilm, etc. In view of the cost and production efficiency, it ispreferred to use the former method of providing the physical developmentnuclei layer and the silver halide emulsion layer integrally.

The silver halide emulsion to be used in the present invention can beproduced according to the general preparation method of the silverhalide emulsion in the field of the light-sensitive silver halidephotographic material. The silver halide emulsion can be prepared, ingeneral, by mixing and ripening an aqueous silver nitrate solution andan aqueous halide solution such as sodium chloride and sodium bromide,etc., in the presence of gelatin.

A silver halide composition of the silver halide emulsion layer to beused in the present invention preferably comprises 80 mol % or more ofsilver chloride, particularly preferably 90 mol % or more of silverchloride. By making the silver chloride content high, conductivity ofthe formed physically developed silver increases.

The silver halide emulsion layer to be used in the present invention haslight-sensitivity to various kinds of light sources. As one of themethods for preparing an electromagnetic wave shielding material, theremay be mentioned, for example, a method in which a physically developedsilver having a fine line pattern shape such as a lattice-like pattern,etc. is formed. In this case, the silver halide emulsion layer isrevealed to a fine line pattern shape, and as the exposing methods,there are a method in which a transparent pattern mask with a fine linepattern and a silver halide emulsion layer are closely contacted andexposed with ultraviolet rays, or a method in which scanning exposure iscarried out by using various kinds of laser beams. In the former contactexposure using ultraviolet rays, it can be carried out even whensensitivity of the silver halide is relatively low, but in the case ofscanning exposure using laser beam, a relatively high sensitivity isrequired. Accordingly, when the latter exposure method is employed, toenhance sensitivity of the silver halide, chemical sensitization orspectral sensitization using a sensitizing dye may be applied to thesilver halide. As the chemical sensitization, there may be mentioned ametal sensitization using a gold compound or a silver compound, a sulfursensitization using a sulfur compound, or both sensitizations are usedin combination. It is preferably a gold-sulfur sensitization using agold compound and a sulfur compound in combination. In the method ofexposing with the above-mentioned laser beam, by using laser beam havingan oscillation wavelength of 450 nm or shorter, for example, using bluecolor semiconductor laser (which is also called to as violet laserdiode) having an oscillation wavelength of 400 to 430 nm, it is possibleto handle the material under room light (under light yellow fluorescentlight).

In the present invention, a dye or a pigment for preventing fromhalation or irradiation may be contained in an optional portion of thetransparent substrate on which a physical development nuclei layer is tobe provided, for example, in an adhesive layer, an intermediate layer, aphysical development nuclei layer or a silver halide emulsion layer, orin a back coating layer provided at the back surface of the substrate.

When an electromagnetic wave shielding material is to be prepared byusing a light-sensitive material in which a silver halide emulsion layeris provided on a physical development nuclei layer directly or throughan intermediate layer, a silver complex diffusion transfer development(the DTR development) (DTR development) occurs by exposing closelycontacting a transparent pattern mask with an optional fine line patternsuch as a lattice-like pattern with the above-mentioned light-sensitivematerial, or, subjecting the above-mentioned light-sensitive material toscanning exposure using an output machine which can emit various kindsof laser beams with an optional fine line pattern digital image, andthen, treating the resulting material in an alkali solution in thepresence of a soluble silver complex salt-forming agent and a reducingagent, whereby silver halide at an unexposed portion is dissolved tobecome a silver complex salt, and reduced on physical development nucleito precipitate metal silver, so that a physically developed silver thinfilm with a fine line pattern can be obtained. The exposed portionbecomes black silver by being chemically developed in the silver halideemulsion layer. After the development, the silver halide emulsion layerand the intermediate layer, or the protective layer provided dependingon the necessity are removed by washing, whereby a physically developedsilver thin film with fine line pattern is revealed at the surface.

The removing method of the silver halide emulsion layer, etc., providedon the physical development nuclei layer after the DTR development mayinclude a method in which they are removed by washing with water, orthey are peeled off by transferring them to a peeling paper, etc.Removal by washing with water may include a method in which they areremoved by using a scrabbling roller, etc. while spraying hot water as ashower, or a method in which they are removed by jet spraying hot waterwith a force of water.

On the other hand, when a soluble silver complex salt is fed from asilver halide emulsion layer provided on a different substrate from atransparent substrate on which a physical development nuclei layer hasbeen coated, a physically developed silver thin film with a fine linepattern precipitated on physical development nuclei can be obtained bysubjecting a silver halide emulsion layer to exposure in the same manneras mentioned above, the transparent substrate on which the physicaldevelopment nuclei layer has been coated and the differentlight-sensitive material on which the silver halide emulsion layer hasbeen coated are closely contacted in an alkali solution in the presenceof a soluble silver complex salt-forming agent and a reducing agent, andafter taking out the material from the alkali solution, both materialsare peeled apart after a lapse of several tens seconds to severalminutes.

Next, a soluble silver complex salt-forming agent, a reducing agent, andan alkali solution to be required for the silver complex diffusiontransfer development are explained. The soluble silver complexsalt-forming agent is a compound which dissolves silver halide to form asoluble silver complex salt, the reducing agent is a compound to reducethe soluble silver complex salt to precipitate metal silver on thephysical development nuclei, and these reactions are carried out in analkali solution.

As the soluble silver complex salt-forming agent to be used in thepresent invention, there may be mentioned a thiosulfate such as sodiumthiosulfate, ammonium thiosulfate, etc., a thiocyanate such as sodiumthiocyanate, ammonium thiocyanate, etc., alkanol amine, a sulfite suchas sodium sulfite, potassium hydrogen sulfite, etc., compounds describedin The Theory of the Photographic Process, edited by T. H. James, 4^(th)Edition, pp. 474 to 475 (1977), and the like.

As the reducing agent to be used in the present invention, developingagents known in the field of photographic development may be used. Theremay be mentioned, for example, polyhydroxybenzenes such as hydroquinone,catechol, pyrogallol, methylhydroquinone, chlorohydroquinone, etc.,3-pyrazolidones such as 1-phenyl-4,4-dimethyl-3-pyrazolidone,1-phenyl-3-pyrazolidone,1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, etc.,p-methyl-aminophenol, p-aminophenol, p-hydroxyphenylglycine,p-phenylenediamine, and the like.

The above-mentioned soluble silver complex salt-forming agent and thereducing agent may be coated with the physical development nuclei layeron the transparent substrate, may be added into the silver halideemulsion layer, or may be added into the alkali solution, and furthermay be added to a plural number of positions, and it is preferred to addto at least into the alkali solution.

A content of the soluble silver complex salt-forming agent into thealkali solution is suitably used in the range of 0.1 to 5 mol per literof the developing solution, and a content of the reducing agent issuitably used in the range of 0.05 to 1 mol per liter of the developingsolution.

A pH of the alkali solution is preferably 10 or higher, more preferably11 to 14. As the alkali agent, sodium hydroxide, potassium hydroxide,sodium triphosphate, amino alcohol, etc., may be used. A developing timeis preferably 5 to 60 seconds, more preferably 7 to 45 seconds or so. Adeveloping temperature is preferably 10 to 40° C., more preferably 15 to35° C. or so. In the present invention, a method of applying the alkalisolution to carry out the silver complex diffusion transfer developmentmay be a dipping system or a coating system. The dipping system iscarried out, for example, by transporting a transparent substrate onwhich a physical development nuclei layer and a silver halide emulsionlayer are provided while dipping it in an alkali solution stored in atank with a large amount. Also, the coating system is, for example, tocoat an alkali solution on a silver halide emulsion layer with an amountof 40 to 120 ml or so per 1 m².

By the way, as mentioned above, as the fine line pattern, there is apattern, for example, in which fine lines with a line width of 10 to 100μm or so are provided in a lattice state to lengthwise and crosswisedirections. When line widths are made small and intervals between linesare made large, then light transmittance is improved but conductivity islowered. To the contrary, when the line widths are made large andintervals between lines are made small, then light transmittance islowered while conductivity is heightened. When such a fine line patternis provided on a transparent substrate with a total luminoustransmittance of 70 to 90% or so, the physically developed silver withan optional fine line pattern formed on a transparent substrate alone isdifficult to satisfy both of the light transmittance of a total luminoustransmittance of 50% or higher and the conductivity of a surfaceresistance of 10 ohm/□ or less simultaneously. The reason is that thisphysically developed silver has the conductivity of a surface specificresistance of 50 ohm/□ or less, preferably 20 ohm/□ or less, and when itwas made a total luminous transmittance of 50% or higher with a fineline width of 40 μm or less, for example, with a pattern of a fine linewidth of 20 μm, the surface resistance becomes several hundreds ohm/□ toseveral thousands ohm/□ or higher. However, this physically developedsilver itself has conductivity since a firm silver image has beenformed. Thus, when such a fine line pattern having a thickness of 15 μmor less and a line width of 40 μm or less is provided on a transparentsubstrate with a total luminous transmittance of 70 to 90% or so byapplying plating using a metal such as copper or nickel, especiallyapplying electrolytic plating, the resulting material has theconductivity of a surface resistance of 10 ohm/□ or less, preferably 7ohm/□ or less to 0.001 ohm/□ even when the light transmittance thereofis a total luminous transmittance of 50% or higher, preferably 60% orhigher.

A thickness of the fine line pattern formed by metal plating can beoptionally varied depending on the desired characteristics, andpreferably in the range of 0.5 to 15 μm, more preferably in the range of2 to 12 μm. When the thickness is thinner than the above range, adesired surface resistance value sometimes cannot be obtained, while thethickness is thicker than the above range, there is no significantproblem, but a decreasing effect of the surface resistance value cannotbe expected whereas efficiency of plating work is lowered. Also, theelectromagnetic wave shielding material of the present invention canprovide a shielding effect of 30 dB or more over the higher frequencyband of 30 MHz to 1,000 MHz or more.

In the present invention, plating of the physically developed silver ofthe fine line pattern can be carried out by either of the electrolessplating method, the electrolytic plating method or the plating method inwhich both of the above are combined. For producing the electromagneticwave shielding material of the present invention, it is preferred to usethe method of electrolytic plating or electroless plating is used incombination thereto, in the viewpoint that a role of the treatments ofat least exposure of the fine line pattern, developing treatment andplating treatment can be applied continuously with a roll state as suchto a continuous web in a roll state in which a physical developmentnuclei layer and a silver halide emulsion layer have been formed on atransparent substrate and in view of working efficiency of plating. Theplating layer of the physical development silver of the fine linepattern has a high electric conductivity, so that electrolytic platingcan be carried out easily.

In the present invention, the metal plating method can be carried out bythe conventionally known method. For example, the electrolytic platingmethod can be carried out by using a metal such as copper, nickel,silver, gold, solder, or copper/nickel, etc., and the conventionallyknown method in which a multi-layer or a composite type electrolyticplating film(s) thereof are formed can be used. With regard to thesetechniques, literatures such as “Surface Treatment TechniqueComprehensive; K. K. Gijutsu Shiryo Center, Dec. 21, 1987 InitialEdition, pp. 281 to 422”, and the like can be referred to.

It is preferred to use copper and/or nickel since plating is easy,conductivity is excellent, plating can be carried out with a thick film,and cost is low. Examples of the electrolytic plating may include amethod in which the above-mentioned transparent substrate on which thephysically developed silver has been formed is dipped in a bathcomprising copper sulfate and sulfuric acid, etc., as main componentsand passing electricity with a current density of 1 to 20 ampere/dm² at10 to 40° C.

In the electromagnetic wave shielding material of the present invention,when the fine line pattern has a thickness of 0.5 to 15 μm and a linewidth of 1 to 40 μm, it can show excellent light-transmitting propertyand conductive property of a total luminous transmittance of 50% orhigher, and a surface resistance of 10 ohm/□ or less, and show ashielding effect of 30 dB or more over higher frequency region of 30 MHzto 1,000 MHz or more. And the shielding effects can be expectedsufficiently over higher frequency bands of several tens GHz bands.

The electromagnetic wave shielding material of the present invention mayhave an optional layer at the side having the electromagnetic waveshielding layer or at the opposite side of the substrate, for example, aprotective layer, a near infrared absorption layer, etc., and theselayers may be provided by coating or adhering a film.

Also, for the purpose of making it easier to see a scene through thefine line pattern(s), it is preferred to subject the surface of theplating layer to a blackening treatment by using an acid or an alkali,or by plating.

EXAMPLE

In the following, the present invention is explained in more detail byreferring to Examples.

Example 1

A polyethylene terephthalate film having a thickness of 100 μm and atotal luminous transmittance of 89% was used as a transparent substrate.This film substrate has a subbing layer comprising a vinylidene chlorideand a gelatin layer with 50 mg/m². On the above film, a hydrosolsolution containing 0.4 mg/m² of palladium sulfate in terms of a solidcontent was coated and dried to form a physical development nucleilayer.

Subsequently, a silver halide emulsion layer (prepared so that itbecomes 90 mol % of silver chloride and 10 mol % of silver bromide, andan average particle size of 0.23 μm) prepared by a general double-jetmixing method of a silver halide emulsion for photography was coated onthe above-mentioned physical development nuclei layer. It was coated sothat a weight ratio of silver (silver nitrate)/gelatin in the silverhalide emulsion layer became 1.5 and a silver halide amount (calculatedon silver nitrate) of 4 g/m² to prepare a light-sensitive material.

This light-sensitive material was exposed through a transparent patternmask with a fine line pattern using a daylight film vacuum contactprinter which employs a mercury lamp as a light source, subsequentlydeveloped by dipping in a commercially available developer for a silvercomplex salt diffusion transfer at 25° C. for 40 seconds, and then,washed away the silver halide emulsion layer to form a physicallydeveloped silver thin film with a fine line pattern which has a fineline width of 20 μm, a thickness of the fine line of 0.05 to 0.1 μm anda fine line interval of 200 μm.

The total luminous transmittance of the electromagnetic wave shieldingmaterial (Comparative sample 1) in which a fine line pattern statesilver thin film had been formed obtained as mentioned above was 76%.The surface resistance value of the Comparative sample 1 was measuredaccording to the measurement method of JIS K 7194. As a result, thesurface resistance value was 850 ohm/□. Also, Comparative sample 1showed a shielding property of 27 dB at 500 MHz and of 23 dB at 1,000MHz. For the reference purpose, the above-mentioned light-sensitivematerial was developed without exposure in the same manner as inComparative sample 1 and a physically developed silver thin film wasformed on the whole surface. The surface specific resistance of thissample was 13 ohm/□.

Next, the above-mentioned Comparative sample 1 was subjected toelectrolytic plating treatment as mentioned below. Using a processingsolution for an electrolytic copper plating (copper sulfate: 75 g/l,sulfuric acid: 190 g/l, chloride ion: 50 ppm), and according to thepredetermined method (25° C., 3 A/cm²), copper plating was applied onthe physically developed silver film with a thickness of 5 μm to prepareSample A of the present invention. As a result of the measurements ofthe total luminous transmittance and the surface resistance value in thesame manner as in Comparative sample 1, Sample A of the presentinvention had the total luminous transmittance of 73% and the surfaceresistance value of 0.5 ohm/□, and it showed a shielding property of 56dB at 500 MHz and of 63 dB at 1,000 MHz.

Example 2

In the same manner as in Example 1 except that a plating solutioncomprising copper and a plating solution comprising nickel were used,and an electrolytic plating of copper and nickel with a total filmthickness of 5 μm was applied, Sample B of the present invention wasprepared. As results of the measurements of the total luminoustransmittance and the surface resistance value, Sample B of the presentinvention had the total luminous transmittance of 71% and the surfaceresistance value of 0.3 ohm/□, and it showed a shielding property of 60dB at 500 MHz, and of 64 dB at 1,000 MHz.

INDUSTRIAL APPLICABILITY

According to the present invention, an electromagnetic wave shieldingmaterial having excellent light transmittance and shielding propertyover wide frequency bands can be obtained.

1. An electromagnetic wave shielding material which comprises atransparent substrate, physically developed nuclei laid thereon, a layerof physically developed silver having a fine line pattern formed on saidnuclei, and a metal film plated on said physically developed silver,wherein the fine line pattern has a line width of 40 μm or less, a totalluminous transmittance of 50% or higher, and a surface resistance of 10ohm/□ or less.
 2. The electromagnetic wave shielding material accordingto claim 1, wherein the fine line pattern has a thickness of 15 μm. 3.The electromagnetic wave shielding material according to claim 2,wherein the total luminous transmittance is 60% or higher.
 4. Theelectromagnetic wave shielding material according to claim 2, whereinthe surface resistance is 7 ohm/□ or less.
 5. The electromagnetic waveshielding material according claim 2, wherein the thickness of the fineline pattern is 0.5 to 15 μm.
 6. The electromagnetic wave shieldingmaterial according to claim 5, wherein the thickness of the fine linepattern is 2 to 12 μm.
 7. The electromagnetic wave shielding materialaccording to claim 2, wherein the line width of the fine line pattern is1 to 40 μm.
 8. The electromagnetic wave shielding material according toclaim 1, wherein the plating is an electrolytic plating.
 9. Theelectromagnetic wave shielding material according to claim 1, whereinthe plating is at least one kind of plating selected from copper andnickel.
 10. A process for preparing an electromagnetic wave shieldingmaterial which comprises exposing a light-sensitive material having aphysical development nuclei layer and a silver halide emulsion layer ona transparent substrate in this order, precipitating metal silver with apattern having an optional fine line onto the physical developmentnuclei layer by physical development, then, removing a layer provided onthe physical development nuclei layer, and subjecting to plating a metalwith the use of the physically developed metal silver as a catalyticnucleus to obtain an electromagnetic wave shielding material having afine line pattern.
 11. The process for preparing an electromagnetic waveshielding material according to claim 10, wherein the fine line patternafter the metal plating has a thickness of 15 μm or less and a linewidth of 40 μm or less, a total luminous transmittance of 50% or higher,and a surface resistance of 10 ohm/□ or less.
 12. The process forpreparing an electromagnetic wave shielding material according to claim11, wherein the total luminous transmittance is 60% or higher.
 13. Theprocess for preparing an electromagnetic wave shielding materialaccording to claim 11, wherein the surface resistance is 7 ohm/□ orless.
 14. The process for preparing an electromagnetic wave shieldingmaterial according to claim 11, wherein after the metal plating thethickness of the fine line pattern is 0.5 to 15 μm.
 15. The process forpreparing an electromagnetic wave shielding material according to claim14, wherein after the metal plating the thickness of the fine linepattern is 2 to 12 μm.
 16. The process for preparing an electromagneticwave shielding material according to claim 11, wherein after the metalplating the line width of the fine line pattern is 1 to 40 μm.
 17. Theprocess for preparing an electromagnetic wave shielding materialaccording to claim 10, wherein the plating is an electrolytic plating.18. The process for preparing an electromagnetic wave shielding materialaccording to claim 10, wherein the plating is at least one kind ofplating selected from copper and nickel.
 19. The process for preparingan electromagnetic wave shielding material according to claim 18,wherein an electrolytic plating is carried out by dipping a transparentsubstrate on which a physically developed silver has been formed in abath containing copper sulfate and sulfuric acid as main components witha current density of 1 to 20 ampere/dm² at 10 to 40° C.